Thermoplastic polyurethanes (TPU) are useful materials well known in the art. They are generally prepared by reacting a polyisocyanate with a polyol and optionally a chain extender. The resulting materials have many useful properties and are used in a wide variety of applications.
TPU contain hard segments and soft segments, where the soft segments are typically polyester based or polyether based. Polyester TPU suffer from hydrolytic degradation while polyether TPU are prone to oxidative and/or thermal degradation. There is an ongoing need for TPU materials that have the expected useful properties but which also provide improved hydrolytic, oxidative and/or thermal stability.
There is also a desire to improve the adhesion of TPU materials to polar materials such as polyamides or polyesters, for example Nylon-6,6. Currently the ability to use TPU materials in combination with polar materials is limited due to the relatively poor adhesion between existing TPU materials and polar materials, especially where the application involves combining a layer of TPU material with a layer of polar material. The adhesion between the layer is too weak to meet the requirements for many applications where such a layer combination would otherwise be very useful. Thus, TPU cannot be used in many applications requiring high levels of adhesion between layers of TPU and other materials, especially polar materials. There is a continuing need for TPU materials with adhesion to other materials, especially polar materials, that would allow TPU to be used in applications where good/improved adhesion to other materials, especially polar materials, is required.
Overall there is a continuing need for an improved TPU material that has the expected useful properties of a polyether and/or polyester TPU but also provides improved hydrolytic, oxidative and/or thermal stability, improved adhesion to polar materials such as polyamides or polyesters, and some combination thereof.